function result = isDateTime(arg)
  % Attempt to convert arg to a System.DateTime and return whether 
  % successful or not
  %
  % Author: David Goldsmith, Wash. State Dept. of Ecology, dgol461@ecy.wa.gov
  % Release date: N/A

    if ~exist('System.DateTime', 'class'), import System.DateTime.*; end
    result = System.DateTime.TryParse(arg);